(1) Field of the Invention
The present invention relates generally to dye tubes for textiles and, more particularly, to a method and apparatus for securing a sheet of filter material around a yarn tube of the type used as a carrier during dyeing or finishing.
(2) Description of the Prior Art
Yarn is commonly wound around a supporting tube or carrier in preparation for dyeing or finishing. A plurality of yarn carrying tubes are then positioned onto a spindle and immersed in a dye bath or other treatment bath. The tubes also may be axially compressed on the spindle to permit increased loading and improved uniformity of dye penetration by reducing the tension of the yarn on the package.
Modern dye tubes are normally formed of a molded plastic, such as polypropylene, and have a plurality of peripherally extending ribs and/or rings, often of a circumferential or helical configuration, connected by flexible joining members. The ribs and/or rings and joining members together form an open structure permitting dye or other liquids to enter the yarn from the hollow interior of the dye tube. Such tubes are shown in U.S. Pat. Nos. 4,702,433 and 5,445,335, the entire disclosures hereby incorporated by reference.
These perforated dye tubes may be covered with a permeable sleeve or covering to filter the dye bath before the bath contacts the yarn and to help prevent the yarn from being trapped in the compressed tube. Historically, this sleeve was formed of paper. However, since most dye tubes are now recycled after use, the sleeve can of the same general chemical composition as the tube. For example, the tube may be of injection molded polypropylene and the sleeve may be formed of a sheet of spun-bonded, nonwoven polypropylene fibers.
Since dye tubes are subjected to physical stress and high temperatures during use, it is necessary to ensure that the sleeve is securely fastened about the circumference of the dye tube. In addition, the sleeve must by positioned around the tube in an rapid and economical manner.
U.S. Pat. No. 4,385,480 to Burchette, Jr., and U.S. Pat. No. 4,621,508 to Baxley, Jr., are examples of prior art methods and apparatus for wrapping a sleeve around a dye tube, the entire disclosures hereby incorporated by reference. Generally, the technique described in these patents involves feeding tubes positioned end-to-end along an axial pathway while rotating the tubes. A continuous band of covering material is then fed along an angular path to the tubes at a covering station, where the band is wrapped in a spiral about the tubes with the edges of the band being overlapped.
The covering is then adhered to itself and to the tube at the overlap of the sheet edges to form the sleeve. In the Burchette, Jr. patent, the covering material is paper, and the adhesion is achieved with heat and glue, while the covering is the Baxley, Jr. patent is spunbonded, nonwoven polypropylene and the adhesion is with ultrasonic welding without glue. The band is then cut at the joinder of the tubes to form the finished product. Heating and gluing is complicated and ultrasonic welding is expensive but Baxley, Jr specifically taught that heating alone could not be used to provide adequate sealing of the edges of the sheet.
Thus, a need exists for a method and apparatus for securely attaching a covering to the outer surface of a dye tube in a rapid and economical manner while, at the same time, does not require the use of glue or ultrasonic welding and overcomes the problems of using heat to seal the fabric edges.